Process for the manufacture of the arsenates of the alkaline-earth metals



Patente-'d July. 14, 1925.

UNITED STATES 1,545,813 PATENT orifice.

-maN anrwneo, orLYoN, FRANCE, AssIGNoa rro socmrnonmmun mas UsrNEs nu RHONE, or raars, FRANCE. 4

PEQGE'ITSS FOB TEE MANUFACTURE OF THE ARSENATES 0F '1HE AALKAlIlIllfnllEARTH METALS.

No Drawing To all 'wlw/m. it may concem:

Be it known that I, JEAN ALTWEGG, residing at.Lyon, .F rance, a citizen of the Confederation of Switzerland, have in- 5 vented certain new and useful Improvements in Processes for the Manufacture of the Arsenates of the Alkaline-Earth Metals,

of which thefollowing is a specification.

The purpose of 'this invention is the manul facture of the arsenates of the alkalineearth metals. It has been found that they canbe easily obtained on alarge scalein heating the corresponding arsenites, or a mixtures-of oxides or hydroxides 4nf alkalinel5' earth metals with arsenious oxide (As20) in resence of a suicient quanity of oxygen. arsenites of the alkaline-earth metals may be prepared by heating a mixture of arsenious oxide' and of a hydroxide of an all1 kalin'efearth metal. Q The arsenites, when heated in an atmosphere of oxygen, exhibit a great ainity for the latter, particularly above about 350 C. It is, besides, not necessary to use pure oxy.- gen, and the oxygen may be diluted` with inert gases; Afor instanceatmospher1c air may be quite well utilized. In this case,

however, caremust be taken to renew constantly the'air supplied, for if it becomes o too poor ino gen, there is a risk of forma;

p -tion of meta ic arsenic. "1*

' The condit ons .under vwhich 4the processn which forms the object' of the invention 'may be carried out are very varied. For inL 6 stance, arsenite may be put in en iron tube, raised to the necessary temperature, in which is made to pass a.. current of. air so 4regulated that no formation of' metallic arsenic can take, place. Arsenite can also 0 be'heated in aclosed Lvessel in communica- ,rtion with a source, 'o f oxygen. By theuselitres :of water and heated tolboiling. The.

0 calcium, 'arsenite formed is. filteredfoiitand heatedjv in a strong currentfof air, the tem,-

perature beingl gradually raised to .about- Application iIedJune V16, 1923. Serial 110.345,92?.

'as to prevent .the

The calcium larsenate is obtained in the form ofa pulverulent mass, which may be at once utilized for agricultural purposes;

There is no objection to the use of a quantity ofliine greater than that mentioned inv the above example if less rich arsenate, containing -free lime, is not objected to.

As has been said above, 'it is not necessary to start with an arsenite prepared for the purpose; a dry mixture of arsenious oxide with the oxide or hydroxide ofthe correspondingalkaline-earth metal may beused. The mixture, on being heated in a stream of air, preferably near 450 C., absorbs the.

oxygen and is. transformed into the correspondin arsenate.

What claim and desire to secure by Letters Patent is 1- A process o manufacture of the arsenatesof the .alkaline-earth metals, consisting in heating the arsenite of an alkalineearth metal whilesupplying a continuous 'current of oxygen thereto, the supply of oxygen being regulated so as to prevent the formation of -metallic arsenic.

2. A process of manufacture of the arsenates of the alkaline-earth metals, consisting in heating a mixture of arsenious oxide with the oxide of .an alkaline-earth metal whilesupplying a continuous current thereto, the.supply of oxytgen being regulated so ormation o metallic arsema.

3- A' of' manufacture of thearsenates othe alkaline-earth metals, f consisting-in heatin a -mixture 'of arsenious oxide with the hy rated oxide of an alkalineearth metal while suppl' ing a4 continuous currentthereto, the supp y'of oxygen being regulated sc as to prevent the formation o metallic Varsenic` A 4; 'Aprocesslo/manufacture of t-he'. e.r'V sen-atesi-of the alkalinefearth metals,cuonsist-` ing'fin heating a dry. mixture' of arsenious oxide with the hydratedo'xide 'of -anfalkel-i .line-earth metalto aboutO-C. Whileslflfp-A plyinga 001115511119118 c'lrrent of ox'y'gen theres4 to, the supplyc oxygen. being regulated so i as togpreventthe'frmation of metallic ar v 5g Alpx'mess4 ofx'nanufacture 'ofthe arsethe-meenemen mangeons-1131;: ing-:Ainheating a mixture ofarseni'ous oxide with the hydrated oxide of an alkaline-earth metal to about 450 C. while supplying e continuous current of atmospheric air thereto, the supply of oxygen being regulated so as to prevent the formation of metallic arsenic;

6. A process of manufacture of calcium `arsenete consisting in heatingmalcium arsenite and -agit'etilngl the same while supplying a. continuous current of oxygen thereto, the supply of oxygen being regulated so as to preventthe formation of metallic arsenic.

7. A process of xnanufsawture of calcium' arsenate consisting in heating a, mixture of arsenious oxide and slaked lime. to about 450 C. and agitating the same while supplying a continuous current of oxygen thereto. y

In testimony whereof I have signed my name tothis specification.

` JEAN ALTWEGG.

oxide with the hydrated oxide of an 'alkaline-earth metal to about 450 C. While supplying a continuous current of atmospheric air thereto, the supply of oxygen being regulated so as to prevent the formation of metallic arsenic.

6. A process of manufacture of calcium arsenate consisting in heating calcium arse-4 nite and `agitatingr` the same while supplying a continuous current of oxygen thereto, the supply of oxygen being regulated so as JEAN ALTWEGG.

Certificateof Correction.

It is hereby certified that in Letters Patent No. 1,545,873, granted July'14, 1925, llon the appllcation of Jean Altwegg, of Lyon,F rance, for an improvement in S rocesses for the Manufacture of the Arsenates of the Alkaline-Earth Metals,

errors appear in the printed s eciication requiring correction as follows: Page 1, line 83, claim 2, and line 92, c aim 3. after the word current insertthe` Words.

of oxygen; and that thesaid LettersPatent should be read with these corrections therein that the same may conform to the record-of the case inthe Patent Office.

Signed and. sealed this 17th 'day of November, A. D. 1925,.

[sEALi] `WM. A. KINNAN Acting Commissioner of Patente.

Certificate of Correction.

It is hereby certified that in Lett/ers Patent No. 1,545,873, granted July 14, 1925, upon the application of Jean Altwegg, of Lyon, F rance, for an improvement in Processes for the Manufacture of the Arsenates of the Alkaline-Earth Metals,

errors' apper'in the printed specification requiring correction as follows: Page l, lline 83, claim 2, and line 92, claim 3, after the word current insertthewords.

of oygeu; and that thesaid Letters Patent Ashould be read with these corrections therein that the same may conform to the recordof the case inthe Potent Oice.

Signed and sealed this 17th 'day of November, A. D. 1925,.

[SEAL] l WM- A. KINNAN,

4 Acting @omissiomr ofPatents, 

